Abstract: Objective:To investigate the risk factors of central lymph node metastasis (CLNM) and lateral neck lymph node me -tastasis in papillary thyroid microcarcinoma (PTMC) patients, and to analyze the importance of high resolution ultrasonography in the diagnosis of lateral neck lymph node metastasis in PTMC patients.Methods:A retrospective protocol was applied, and a total of 1 037 PTMC patients were reviewed. These patients underwent central lymph node dissection or thyroidectomy with lateral neck lymph node dissection between January and November in 2013in the Tianjin Medical University Cancer Institute and Hospital. Clinicopathological factors, namely, age, sex, primary tumor size, multifocality, bilateralism, thyroid capsular invasion, and local invasion, were analyzed. Results: CLNMs were found in 332 of 1037patients ( 32.0% ), and71out of 1037patients had lateral neck lymph node metastasis (6.85%). In the univariate analysis, patients with the following risk factors were at high risk of CLNM (P<0.05): male, aged ≤ 45years old, with primary tumor size of >5 mm, multifocality, bilateralism, thyroid capsular invasion, and local invasion. Male patients with cen-tral lymph node metastasis positively showed high lateral neck lymph node metastasis rate ( P<0.05) according to high-resolution ultra-sonography diagnosis. The rate of lateral neck lymph node metastasis increased with increasing number of central lymph node metasta -ses. The sensitivity and specificity of high resolution ultrasonography for lateral neck lymph node metastasis were 92.96% and 81.48% in PTMC patients. Conclusion:Prophylactic central compartment lymph node dissection needs to be performed in patients with CLNM risk factors (i.e., male, aged ≤ 45years old, primary tumor size of > 5 mm, multifocality, bilateralism, thyroid capsular invasion, and lo-cal invasion). The importance of high-resolution ultrasonography in diagnosing lateral neck lymph node metastasis was revealed by the results. Thus, this method should be widely popularized. Radical neck dissection should be performed in male patients who received a positive diagnosis via ultrasonography or those with PTMC who had more than three positive nodes in the central lymph node metasta-sis. However, given the high occurrence rate of PTMC, a prospective study needs to be conducted in the future.